Behind the Scenes

Tom Elliott

satRdays Auckland 2020

Part I

What is iNZight, and who uses it?

library(iNZight)
iNZight()

iNZight main window

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<img src="assets/images/Rlogo.svg" class="logo" > package!
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GUI for __visually exploring__ data
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__easy-to-learn__ tool for students/beginners ...
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... but also non-beginners!

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<img src="assets/images/Rlogo.svg" class="logo" > package!
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GUI for __visually exploring__ data
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__easy-to-learn__ tool for students/beginners ...
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... but also non-beginners!
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bridge between __GUI__ and __coding__

Data

GUI

Explore

Save script

Part II

The development of iNZight

Another child of the University of Auckland

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Chris Wild
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Statistics __students__

How does it work?

gWidgets2 + gWidgets2RGtk2† RGtk2‡ GTK

† John Verzani ‡ Michael Lawrence

Started off small … 

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a __feature__ here ...
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a __module__ there ...

… et voilà: a rewrite was needed! 

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Object Oriented Programming (OOP)
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Separability
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Reactivity
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Extensibility

Object Oriented Programming

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reference classes
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each __component__ of the UI is represented by a __class__
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classes have __properties__ ("fields") and __methods__

LoadDataWindow <- setRefClass("LoadDataWindow",
    fields = list(
        filename = "character"
    ),
    methods = list(
        initialize = function(...) {
            w <- gwindow("Load data")
            g <- ggroup(horizontal = FALSE, container = w)

            # Get filename from user
            fileedit <- gedit(container = g)

            # Load data
            loadbtn <- gbutton("Load", container = g)

            addHandlerKeystroke(fileedit,
                handler = function(h, ...) {
                    filename <<- svalue(h$obj)
                }
            )

            addHandlerClicked(loadbtn, function(h, ...) loadData())
        },
        loadData = function() {
            data <- read.csv(filename)
        }
    )
)

Demo Load Window

iNZight main window

Separability

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keep UI and data logic separate
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UI inputs control arguments to a __single function__
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existing or new __wrapper__ for another __package__

LoadDataWindow <- setRefClass("LoadDataWindow",
    fields = list(
        filename = "character"
    ),
    methods = list(
        initialize = function() { ... },
        loadData = function() {
            data <- read.csv(filename)
        }
    )
)

LoadDataWindow <- setRefClass("LoadDataWindow",
    fields = list(
        filename = "character",
        filetype = "character",
        delimiter = "character", # csv can use , or ;
        ...
    ),
    methods = list(
        initialize = function(...),
        loadData = function() {
            if (filetype == "csv") {
                data <- read.csv(filename, delimiter = delimiter, ...)
            } else if (filetype == "excel") {
                data <- readxl::read_xls(filename, ...)
            } else ...
        }
    )
)

LoadDataWindow <- setRefClass("LoadDataWindow",
    fields = list(
        filename = "character",
        filetype = "character",
        delimiter = "character", # csv can use , or ;
        ...
    ),
    methods = list(
        initialize(...),
        loadData = function() {
            data <- iNZightTools::smart_read(filename,
                filetype = filetype,
                delim = delimiter,
                ...
            )
        }
    )
)

Reactivity

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<strong>Instant</strong> feedback
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Makes <strong>exploring</strong> data <strong>faster and easier</strong>
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Widget <strong>handlers</strong> and <strong>separability</strong>

Demo <- setRefClass("Demo",
    field = list(
        data = "data.frame",
        colour = "character"
    ),
    methods = list(
        initialize = function() {
            w <- gwindow("Demo")
            g <- ggroup(horizontal = FALSE, container = w)
            col <- gcombobox(
                c("Orangered", "Goldenrod", "Steelblue"),
                container = g,
                handler = function(h, ...) {
                    colour <<- svalue(h$obj)
                    draw()
                }
            )

            data <<- data.frame(x = rnorm(100), y = rnorm(100))
            colour <<- "Orangered"

            draw()
        },
        draw = function() {
            plot(y ~ x,
                data = data,
                col = colour
            )
        }
    )
)

Extensibility

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<strong>Foresight</strong> and <strong>planning</strong>
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Add <strong>new</strong> or change <strong>existing</strong> features ...
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... without rewriting everything!
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<strong>OOP:</strong> add new classes, inheritance, ...
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<strong>Separability:</strong> new field = new argument<br>everything else unchanged
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A system for adding __completely new__ modules

DemoModule <- setRefClass(
    "Demo Module",
    contains = "CustomModule",
    fields = list(
        GUI = "ANY",
        ...
    ),
    methods = list(
        initialize = function(gui, name) {
            callSuper(gui,
                name = name,
                embedded = TRUE
            )
            ...
        },
        ...
    )
)

Thank you

Slides: bit.ly/iNZightSatRday